<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <span class="iconfont header-abs-back">&#xe624;</span>
    </router-link>
    <div
      class="header-fixed"
      v-show="!showAbs"
      :style="opacityStyle">
      <router-link tag="div" to="/">
        <span class="iconfont header-fixed-back">&#xe624;</span>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      // console.log(document.documentElement.scrollTop)
      const top = document.documentElement.scrollTop
      if (top > 60) {
        this.showAbs = false
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity: opacity
        }
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import "~styles/varibles.styl"
  .header-abs
    position absolute
    left .2rem
    right .2rem
    top .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    text-align center
    line-height .8rem
    background rgba(0, 0, 0, 0.8)
    .header-abs-back
      color #ffffff
      font-size .4rem
  .header-fixed
      z-index 2
      position fixed
      top 0
      left 0
      right 0
      height $headerHeight
      line-height $headerHeight
      text-align center
      color #fff
      background $bgColor
      font-size .32rem
      .header-fixed-back
        position absolute
        top 0
        left 0
        width .64rem
        text-align center
        font-size .4rem
        color #fff
</style>
